1. Field of the Invention
This invention relates to a ball mill with a grinding chamber partially filled with grinding bodies and lined with a wearing plate with a fixed body in the form of a shaft extending in the direction of the axis of the tubular chamber and supported by radial arms distributed in a longitudinal direction and supported on the wearing plate which is in turn supported within the wall of the grinding chamber. The structure relates to structures of the type shown in the copending patent application, Ser. No. 212,326, Filed Dec. 27, 1971, Now U.S. Pat. No. 3,838,825.
2. Description of the Prior Art
The term ball mills as used herein refers generally to vibratory driven mills which have movable bodies such as balls or rods therein that affect grinding by impacting the material between the movable bodies or between the bodies and the wall of the grinding chamber. In ball mills, the comminution or grinding effect greatly decreases inwardly from the outer wall on account of the damping which occurs to the movable bodies by means of the grinding material. Therefore, with larger grinding containers, the comminution output becomes unsatisfactory and with increased volume, the grinding effect diminishes. It has, therefore, been arranged to provide a fixed body in the form of a center shaft or pipe in the grinding container to shorten the distance between each of the movable bodies and a fixed body. In a tubular shaped grinding container, the center fixed axis is extended parallel to the axis of tubular container.
With this construction, it was possible to transfer the vibrating movement of the grinding container so that it affected the grinding material lying some distance from the wall of the chamber with equal intensity to that lying against the wall.
However, such shafts or pipes have been welded or secured to the ends of the tubular grinding chamber. With operation, the connections failed, and the shafts tore off of their mounts because of the large stresses incurred in operation after a short time.
From the German laid open Specification No. 2,006,789, constructions for fixed bodies, also known as energization bodies, within the grinding chamber are known. These fixed bodies are fixedly connected through supporting elements or directly on the wall of the grinding chamber, generally the end walls, or are pushed loosely into the grinding pipe or shaft so that support takes place through the supporting elements which are arranged in at least two planes perpendicular to the longitudinal axis of the energizing body. In the case of materials difficult to grind, high accelerating forces are necessary for the introduction of a sufficient amount of comminution energy into the movable grinding bodies that satisfactory and reliable fastenings have been considered too expensive for construction.